为研究不同种类添加剂对地聚合物界面过渡区(ITZ)的影响,设计了变角剪切试验以研究地聚合物材料对界面力学行为的影响,采用Mohr-Coulomb准则表征了界面内摩擦角与黏结强度,并通过扫描电镜结合能谱(SEM-EDS)分析了破裂面的微观结构。研究结果表明:地聚合物与岩石界面的内摩擦角在38°~48°之间,同一组对照实验中界面内摩擦角与黏聚力呈负相关。对于同一种类岩石,强度更高则表现出更高的界面黏结强度。3种纤维材料对矿渣-地聚合物材料与骨料的黏结强度都有积极影响,其中玻璃纤维增强效果最为显著,为3.72MPa。在所有的试验结果中,硅灰对界面黏聚力的增强效果最大,为3.79MPa。ITZ仍是矿渣-地聚合物混凝土中最薄弱的区域,SEM-EDS检测结果表明地聚合物-岩石界面过渡区域主要存在于地聚合物材料中,界面过渡区域宽度在10~20μm之间。

In order to study the impact of different types of additives on the interfacial transition zone (ITZ)of the geopolymer interface, this study employs a variable angle shear test to study the impact of the interface mechanical behavior of geopolymer materials. The Mohr-Coulomb criterion is used to char- acterize the friction angle and bonding strength within the interface. The microstructure of the fracture surface is analyzed by scanning electron microscopy and energy spectroscopy (SEM-EDS). The research results show that the internal friction angle at the interface between geopolymer and rock ranges between 38° and 48°. In the same set of control experiments, the internal friction angle at the interface is nega- tively correlated with the cohesion force. For the same type of rock, higher strength shows higher interfa- cial bonding strength. The three fiber materials have a positive impact on the bonding strength of theslag-geopolymer material and aggregate, among which the glass fiber reinforcement effect is the most significant, at 3.72 MPa. Among all test results, silica fume has the greatest enhancement effect on in- terfacial cohesion, which is 3.79 MPa. ITZ is the weakest zone in slag-geopolymer concrete. SEM-EDS test results show that the surface geopolymer-rock interface transition zone mainly exists in geopolymer materials, with the width of the interface transition zone between 10 and 20 μm.